Today many different types of plate heat exchangers exist and are employed in various applications depending on their type. Some types of plate heat exchangers have a casing that forms a sealed enclosure in which heat transfer plates that are joined are arranged. The heat transfer plates form a stack of heat transfer plates where alternating first and second flow paths for a first and a second fluid are formed in between the heat transfer plates.
Since the heat transfer plates are surrounded by a casing, the heat exchanger may withstand high pressure levels in comparison with many other types of plate heat exchangers. Some examples of heat exchangers with a casing that surrounds heat transfer plates are found in patent documents EP2508831 and EP2527775. The plate heat exchangers disclosed by these documents handle high pressure levels well. However, in some applications the shell has to be relatively thick to be able to handle the desired pressure levels, which increases the total weight as well as the overall cost of the heat exchanger.
Thus, it is estimated that there is a need for a new type of plate heat exchanger that may withstand high pressure levels, while still requiring relatively less material for its casing than some other types plate heat exchangers do.